A living list of the best Onsen hotels that I've stayed in, as well as a couple of public hot springs you can experience and some educational information & videos about how to best enjoy them.
Onsen come in two forms, hotels (ryokan) and public baths. All the hotels mentioned in this list are Japanese style hotels, with tatami sleeping mats. Each hotel recommendation has a detailed video walk through to show you the room and other parts of the resort experience.